There has been a wide variety of electrical connectors or connector assemblies adapted for insulation-displacement termination of an insulated electrical wire. Such connectors sometimes are called "solderless" connectors. In other words, a typical insulated wire includes a center conductor (which may be solid or stranded) surrounded by an insulating cladding or cover. The connector includes some form of terminal means which pierces through the insulation and establishes direct electrical engagement with the interior conductive core. A typical insulation displacement terminal includes an insulation-piercing slot defined by cutting edges for cutting through the insulation and further defining an electrical contact area for engaging the conductive core of the wire.
The terminals of such insulation displacement connectors most often are fabricated of stamped and formed sheet metal material and typically the forming and "cutting" requirements of the material necessitate that the material be relatively thin. Therefore, it can be understood that the electrical contact area (i.e. the edges of the insulation-piercing slot which contact the conductive core) is relatively small, particular in comparison to a crimped wire connection, for instance. Accordingly, when such an insulation displacement connection is used in applications where it is subject to vibration or shock, the conductive core of the insulated wire is prone to move, bend or deform due to a high level of stress at the contact interface. In fact, continuous bending of the conductive core can result in "work hardening" of the metal conductor which, in turn, causes brittleness and even breakage of the core, and eventual electrical failure. Therefore, in such applications, various forms of strain relief means have been provided for the insulated electrical wire, usually supporting the insulation at a location remote from the electrical contact area or interface.
Among prior attempts to provide strain relief for the electrical wire, one approach is to provide an insulation crimping section on the insulation displacement terminal itself. In other words, one portion (such as a slotted portion) of the terminal pierces the insulation of the wire, and another portion of the terminal is crimped onto the outer insulation of the wire spaced from the insulation-piercing portion. An example of such an approach is shown in U.S. Pat. No. 4,277,124, dated Jul. 7, 1981. One problem associated with such an approach is that a secondary crimping tool must be provided and an additional secondary crimping step must be performed, all of which is costly in terms of time and labor. Other approaches to providing strain relief on the insulated wire include utilizing portions of the housing to support the wire against at least some bending at the contact area or interface. However, most such structures typically are designed to support the wire in only a given direction rather than on all sides of, or circumferentially about, the wire.
The present invention is directed to providing an insulation displacement electrical connector with an improved wire strain relief means which is extremely simple, inexpensive and very effective in providing support for the wire substantially entirely thereabout.